This is a simple permission issue in directadmin. The CSF in directadmin is running a setuid program. So it simply need to enable the setuid permission for the root user in this program. You may need to look into the following file ,

Now login to the directadmin as admin user and check the CSF page. It must work.

About the author

Sherin is an entrepreneur and Linux is his passion. He is well known in the linux world and working with a number of opensource projects and companies. Sherin is currently working as the technical director of Syslint.